Dose 2016

Type of deviations

Systematic deviations Σ

• Treatment preparation errors, random between “patients”, systematic per “patient” (“patient”=planning image set)

• Remains equal for all fractions based on the planning image set

Sources:

•

− CTV delineated from a snapshot (movements)

Delineation errors

−

− Systematic positioning/alignment errors of devices

Random errors σ

Treatment execution errors

•

• Different and uncorrelated between fractions

Sources:

•

Positioning deviations Field uncertainties

−

−